The aim of the proposed work is to develop a low-cost micro analyzer for monitoring workplace exposures to a specific, and acutely toxic, gas, namely hydrogen sulfide. Recent work by Nanomaterials Research Corporation has shown that a new semiconductor compound is highly responsive to low gas concentrations when held near ambient temperature. This unique discovery provides the opportunity for improved discrimination between gas species (a problem with existing metal oxide sensors, which alarm in the presence of other compounds) . -Furthermore, the device should operate at very low power, making it suitable for battery-powered personal exposure monitors. Finally, the interaction between the sensor and the gas is rapidly reversible, enabling continuous monitoring and the acquisition of cumulative exposure data. PROPOSED COMMERCIAL APPLICATION: Hydrogen sulfide is an extremely toxic gas, and exposure to even low concentrations can lead to respiratory system paralysis, fainting, and even death. It occurs in large amounts in natural gas and petroleum and is a common byproduct of many industrial processes. OSHA reports more than 70 occupations where workers are routinely exposed to this gas, many of which involve entering confined spaces where concentrations are often high. Personal exposure monitors can supplement existing technology, providing an added measure of worker safety in these instances.